Update the documentation for 2.0.3

[pmamico]

Docs version is 1.1.0 (https://rawgit.com/peterservice-rnd/robotframework-excellib/master/docs/ExcelLibrary.html)

For example, in 2.0.3 Keyword 'ExcelLibrary.Open Excel Document' expected 3 arguments, not 2, but there is no docs about which 3.